Multi-mode cvt controller

Abstract

A control system for a continuously variable transmission (CVT) is provided. The control system includes a shift mode switch, an actuator and a controller. The shift mode switch is selectable between a plurality of modes. The actuator is in operational communication with the CVT to selectively override normal shifting characteristics of the CVT. The controller is in communication with the shift mode switch. The controller is configured to control the actuator to selectively override the normal shifting characteristics of the CVT based at least in part on a select mode configuration selected by the shift mode switch.

1 . A control system for a continuously variable transmission (CVT), the control system comprising:
 a shift mode switch selectable between a plurality of modes;   an actuator in operational communication with the CVT to selectively override normal shifting characteristics of the CVT; and   a controller in communication with the shift mode switch, the controller configured to control the actuator to selectively override the normal shifting characteristics of the CVT based at least in part on a select mode configuration selected by the shift mode switch.   
     
     
         2 . The control system of  claim 1 , wherein the controller is a transmission control unit. 
     
     
         3 . The control system of  claim 1 , wherein the CVT is one of a belt CVT and a NuVinci CVT. 
     
     
         4 . The control system of  claim 1 , further comprising:
 at least one sensor in communication with the controller, the controller further configured to control the actuator to selectively override the normal shifting characteristics of the CVT based at least in part on received sensor information from the at least one sensor.   
     
     
         5 . The control system of  claim 1 , wherein the at least one sensor is at least one of an engine speed sensor, a CVT input speed sensor, a CVT output speed sensor, a temperature sensor and lubrication pressure sensor and a throttle position sensor. 
     
     
         6 . The control system of  claim 1 , further comprising:
 a memory to store operating instructions and algorithms implemented by the controller.   
     
     
         7 . The control system of  claim 6 , wherein the memory further stores at least one table of variable speed ratios used by the controller based at least in part on a position of the shift mode switch and at least one of vehicle speed and throttle percentage. 
     
     
         8 . The control system of  claim 1 , further wherein:
 the CVT is a NuVinci CVT; and   the controller is configured to manipulate one of a carrier of the CVT to adjust a ratio of the CVT.   
     
     
         9 . A vehicle comprising:
 a motor to generate engine torque;   a drivetrain;   a continuously variable transmission (CVT) positioned communicate torque between the motor and the drivetrain at a select ratio;   a shift mode switch selectable between a plurality of modes;   an actuator in operational communication with the CVT to selectively override normal shifting characteristics of the CVT; and   a controller in communication with the shift mode switch, the controller configured to control the actuator to selectively override the normal shifting characteristics of the CVT based at least in part on a select mode configuration selected by the shift mode switch.   
     
     
         10 . The vehicle of  claim 9 , wherein the controller is at least one of transmission control unit, a vehicle control unit and an engine control unit. 
     
     
         11 . The vehicle of  claim 9 , further comprising:
 at least one sensor in communication with the controller, the controller further configured to control the actuator to selectively override the normal shifting characteristics of the CVT based at least in part on received sensor information from the at least one sensor.   
     
     
         12 . The vehicle of  claim 11 , wherein the at least one sensor is at least one of an engine speed sensor, a CVT input speed sensor, a CVT output speed sensor, a temperature sensor and lubrication pressure sensor and a throttle position sensor. 
     
     
         13 . The vehicle of  claim 9 , further comprising:
 a memory to store operating instructions and algorithms implemented by the controller.   
     
     
         14 . The vehicle of  claim 13 , wherein the memory further stores at least one table of variable speed ratios used by the controller based at least in part on a position of the shift mode switch and at least one of vehicle speed and throttle percentage. 
     
     
         15 . The vehicle of  claim 9 , further wherein:
 the CVT is a NuVinci CVT; and   the controller is configured to manipulate one of a carrier of the CVT to adjust a gear ratio of the CVT.   
     
     
         16 . A method of controlling a continuously variable transmission (CVT), the method comprising:
 detecting the activation of a multi-mode shift mode switch; and   implement operating instructions to adjust a shifting characteristics of the CVT associated with a mode indicated by the activated shift mode switch based at least in part on the position of the activated shift mode switch.   
     
     
         17 . The method of  claim 16 , wherein the mode is associated with one of an all-purpose mode, a hill mode and a snow mode. 
     
     
         18 . The method of  claim 16 , wherein the operating instructions include at least one of changing a gear ratio of the CVT based on an engine revolutions per minute (RPM) and given ground speed, changing an output ratio, changing a gear ratio of the CVT based on an engine revolutions per minute (RPM) to a given throttle output, changing a gear ratio of the CVT based on system parameter time constants. 
     
     
         19 . The method of  claim 16 , wherein the operating instructions include a given set of closed loop control parameters employed between a ratio shift actuator driver input and a calculated speed ratio of the drive in operation. 
     
     
         20 . The method of  claim 16 , further comprising:
 setting a variator speed ratio of the CVT based at least in part on inputs of at least one of throttle position input speed, output speed, engine speed, temperature and lubrication pressure.